Doug-all



(No Model.)

I. S. MoDOUGALL. BOILER 0R VESSEL EMPLOYED IN THE TREATMENT 0E FIBROUS MATERIALS FOR THE MANUFAOTURE OF PAPER PULP AND OE'OTEER PURPOSES.

No. 298,602.. Patented May 13, 1884.

llurrnn Srn'rns ISAAC SHIMTVELL MGDOUGALL, OF MANQHESTER, COUNTY OF LANCASTER ATTENT rarest ENGLAND.

BOILER OR VESSEL EMPLOYED IN THE TREATMENT OF FlBROUS MATERIALS FOR THE MANUFACTURE OF T PAPER-PULP AND FOR OTHER PURPOSES.

SPECIFICATION forming part of Letters Patent No. 298,602, dated May 13, 1884:.

Application filed February 12, 1884. (No model.) Patented in England June 30, 1883, No. 3,257.-

To aZZ whom it may concern:

Be it known that 1, Isaac SHIMWELL Mo DOUGALL, a subject of the Queen of Great Britain and Ireland, and a member of the firm of McDougall Brothers, of Manchester, in the county of Lancaster, England, manufacturing chemists, have invented certain Improvements in Boilers or Vessels Employed in the Treatment of Fibrous Materials for the Manufacture of Paper-Pulp and for other Purposes, (for which I have obtained patents in Great Britain, No. 3,257, dated June 30, 1883, and have made application in France, dated December 21-, 1883,) of which the following is a specification.

My invention relates, principally, to boilers or vessels which are employed for the treatment of fibrous materials or the manufacture of pulp for paper making-and which are lined withlead; but my said invention is also applicable to lead-lined vessels for other pure poses. In such lead-lined vessels a considerable difficulty has hitherto been experienced in keeping the lead in its relative position with the casing when the boiler or vessel is submit ted tohigh temperatures. The repeated action of heat upon the lead causes it to continually increase in area, and thus gradually accumulate into ridges or creases, which soon break and necessitate the relining of the boilers or vessels. Most metalssuch as steel and iron-- expand when heated and return to their original volume on cooling. Lead does not possess this power of returning to its original area after expansion. The particles of lead are supposed to possess an amount of adhesive friction which prevents their contraction to an extent equal to that to which they have expanded. For this reason it is di'lficult to make lead-lined boilers or vessels durable when required to withstand high temperatures.

The object of my invention is to render the lead lining of boilers or vessels durable by providing an arrangement for securing the lead lining to the casin g of the boiler or vessel in such a manner that the creeping or sliding effect of the lead is localized into sufficiently small portions to make the lead lining much more durable for use in boiling papenpulp or for other purposes. According to my said invention I accomplish this by providing a sufficient number of suitable holes through the casing and corresponding holes in the lead lining and passing through both these holes bolts or fast enings having a head or the like on the inside, and being provided on the outside with one or more nuts or other means for tightening or hold ing the lead lining and the outer casing firmly together,so as to hold theleadliningin position to the casing. These bolts or fastenings should, by preference, be fixed at distances not very far apart-say, about from nine to twenty-four inches in every directionaccording to the thickness of the lead lining and the temperature to which the vessel is required to be sub jected; but I do not limit myself to these dista-nces.

TVhere preferable, a washer or washers or metal strips or bands may be placed beneath the heads or the like of the bolts or fastenings to form a wider holding-surface on. the lead lining, and these bands or strips may, if desired, be passed from bolt to bolt or to any convenient number of bolts or fastenings. The bolts may be made of metal which will resist the action of acids; or, when made of other metal,the heads of the bolts or the metal washers, strips, or bands beneath the bolt-heads may be protected from the chemical action of acids by covering the heads of the bolts or the other exposed metal surfaces with lead, which may be burned or melted to the lead lining, thus causing the inner surface of the vessel of lead to be firmly and securely held to the outer casing in such a manner that the creeping action of the lead is localized into limited portions, whereby the durability of the lead lining is enhanced.

In the accompanying drawing, which forms a part of this specification and shows in sec tion part of the wall of a boiler, A represents the outer casing; 13, the lead lining; O, the bolt securing the lining to the outer casing and held by the nut D on the outside, and E a washer inserted under the head of the bolt.

As a further means of protecting the lead lining from unnecessary strain caused by gases condensing within the vessel, a valve may be so arranged as to open when the pressure of terials and for other purposes, composed of an the atmosphere exceeds that within the vessel, outer shell and a lead lining secured together thus preventing the formation of a vacuum. by means of bolts and nuts, substantially as 7 Having now described and particularly asand for the purposes described. I 5 5 certained the nature of my said invention and In testimony whereof I have signed my name the manner in which the same is or may be to this specification in thepreseuee of two subused or carried into eifect, I would observe,in scribing Witnesses.

conclusion, that what I consider to be novel ISAAC SHIMWELL MGDOUGAL'L. and original, and therefore claim as the inven- Witnesses: 10 tion, is ARTHUR O. HALL,

A vessel or boiler for treating fibrous ma- ALBERT E. HALL. 

